Study: Schizophrenia's Hallucinated Voices Drown Out Real Ones

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A new finding in brain science reveals that the voices in a
schizophrenia patient's head can drown out voices in the real
world — and provides hope that people with the disorder can learn
to ignore hallucinatory talk.

The new research pulls together two threads in earlier
schizophrenia studies. Many scientists have noticed that when
patients hallucinate voices, neurons in brain regions associated
with processing sounds spontaneously fire despite there being no
sound waves to trigger this activity. That's an indication of
brain overload.

But when presented with real-world voices, other studies showed,
hallucinating
patients' brains often failed to respond at all, in contrast
with healthy brains. These studies pointed to a stifling of brain
signals.

By analyzing all of these studies together, biological
psychologist Kenneth Hugdahl of the University of Bergen in
Norway found the simultaneous over-stimulation and dampening of
brain signals to be two sides of the same coin. The findings help
explain why schizophrenia patients retreat into a hallucinatory
world. Now, Hugdahl wants to use this knowledge to help patients
reverse that tendency. [ Top
10 Mysteries of the Mind ]

"What if one could train the patient to shift attention away from
the inside voices to voices coming from outside?" Hugdahl said.

Hearing voices that aren't there

To understand how this training would work, it helps to follow
Hugdahl's logic back to the beginning. Schizophrenia is
incredibly complex, he told LiveScience. The disorder is marked
by delusions, hallucinations, breakdowns in thought processes —
as many as 35 separate symptoms, presenting differently in every
patient.

Hugdahl and his colleagues decided to work toward understanding
just one of these symptoms: hallucinations, the most universal
mark of
schizophrenia (about 70 percent to 80 percent of
schizophrenia patients hallucinate). In research published in
2009, the scientists asked hallucinating patients to listen to
sounds through headphones while in a functional magnetic
resonance imaging (fMRI) scanner. These scanners measure
oxygenated blood flow to different brain regions. More blood flow
suggests more activity in a given region.

The headphones played two syllables simultaneously, one in the
left ear and one in the right ear. For example, the right ear
might hear "pa," while the left heard "ta." Patients weren't told
the tones were different, but were asked to report what they
heard.

Healthy patients generally report hearing the syllable played in
the right ear, because the brain is wired for fast transmission
of signals from the right ear to the left temporal lobe where
speech
sounds are processed.

In the absence of outside sound, schizophrenia patients' left
temporal speech regions showed hyperactivity, a testament to the
real-seeming voices they were hearing in their heads. Hugdahl
expected that the addition of real-world sound would only
increase the activity in the left temporal lobe, given that more
stimulus usually means more activation. But that's not what
happened.

"We found, to my big surprise, that they didn't report hearing
the right ear sounds when they were hallucinating,"
he said. "We didn't see activation in the left temporal lobe
either."

A brain paradox

This was a paradox. How could the brain be overreacting to
nothing and yet shutting down when real sounds came along? To
find out if this paradox was real, Hugdahl and University of
Bergen researchers Kristiina Kompus and Rene Westerhausen (who is
also affiliated with Bergen's Haukeland University
Hospital) dug through earlier studies on schizophrenia to see if
other researchers had found the same thing. They found 11 studies
that had compared the brains of schizophrenia patients with those
of healthy people while listening to external sounds, and 12
studies that looked at the brains of hallucinating schizophrenia
participants. No one had ever put two and two together, though —
examining the brains of hallucinating patients while they
listened to external sounds, for example.

The brain-scan results supported Hugdahl and his colleagues'
earlier findings: The paradox appears to be real.

"It obviously must mean that when the hallucinations are taking
place in the brain, they interfere with the perceptual system,
the system which is there to perceive external stimuli," Hugdahl
said.

Training the brain

Hugdahl and his colleagues reported their findings in the October
2011 issue of the journal Neuropsychologia. Now they're taking
the research further. It's possible, Hugdahl said, that the
simultaneous hyperactivation and quieting of the brain signals is
the work of two neurotransmitters, the chemicals that send
signals in the brain. One, GABA, is the major inhibitor of the
brain: It calms things down, dampening activation. An excess of
GABA could be to blame for the lack of response to real-world
voices. [ 10
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A second neurotransmitter, glutamate, could be the cause of the
hallucinations in the first place. Glutamate is an excitatory
chemical that gets the brain buzzing. Extra glutamate in the
right spot could overactivate the left temporal lobe, triggering
false but all-too-real-sounding voices in the mind.

Funded by a prestigious 20 million Norweigen Kroner ($3.5
million) European Research Council Advanced Grant, the
researchers are now conducting brain scans with a tool called
magnetic resonance spectroscopy, which will allow them to measure
levels of GABA and glutamate in various brain regions in
schizophrenia patients.

If the finding holds, it could open doors to new drug treatments
for schizophrenia symptoms, Hugdahl said. In the meantime, he and
his colleagues are trying something outside of the realm of
pharmacology. They want to train patients to ignore internal
voices and listen to words from the real world.

To do this, the research team has developed an iPhone app that
works just like the original dual-hearing experiments.
Schizophrenia patients wear headphones that play them a different
speech sound in each ear, just as in the original experiments.
For 10 or 15 minutes, twice a day, they practice ignoring the
sounds to the normally dominant right ear and report the sounds
they hear in the weaker left ear.

Only two patients have started this training so far, with one
more set to begin next week. At least 20 or 30 will need to
complete the training before Hugdahl and his colleagues can tell
if the exercises help patients control their attention to
competing voices. If it works, it will be a "major breakthrough,"
Hugdahl said. Early signs are providing some hope.

"The first patient we tested said something very interesting, she
said that after she had been using this training for a couple of
weeks, she had the feeling that the voices were not controlling
her as much as before," Hugdahl said. "She had the feeling that
now she could
withstand the voices. She was more in control, it was not the
voices that were in control. And that's a major achievement."

Correction: This article was updated at 5:30
pm ET to reflect the correct grant amount for Hugdahl's work. It
is 20 million Norwegian Kroner, not 20 million Euros.